Removal of dissolved organic compounds from gas and liquids, including drinking water, groundwater, and wastewater among many other types of gas and liquids, is required for the health and safety of the public and the environment and is therefore a standard step in water treatment processes.
Conventional methods for removing organic compounds from gas and liquids involve either physical operations with high energy requirements, or addition of chemical oxidants that may yield undesirable halogenated organic byproducts. Advanced oxidation processes (AOPs) such as ultraviolet/hydrogen peroxide (UV/H2O2), photocatalysis, and sonication use the highly oxidative hydroxyl (OH) radical to degrade chemical contaminants in water and inactivate microorganisms without producing potentially hazardous halogenated species. However, high energy requirements and/or costly chemical additives limit the feasibility of these technologies.
Gas-phase electrical discharge plasma generated upon the surface of water has been shown to degrade dissolved organic compounds and inactivate microorganisms with high energy efficiency and no chemical additives. Similar to other AOPs, the effect of electrical discharge plasma is through the production of OH radicals. However, unlike many AOPs, the OH radicals are produced directly from the water, rather than through reactions with chemical additives (i.e. H2O2 or ozone). While much research has been done to advance the field of plasma-based water treatment, the lack of effective and scalable reactors has held back the wide-spread use of the technology.
Accordingly, there is a need in the art for more effective and affordable methods and systems for removing organic compounds from gas and liquids using electrical discharge plasma.